Commercial and consumer imaging devices, such as printers, plotters, and facsimile machines, may employ drop on demand inkjet technology for producing printed media. These imaging devices form an inkjet image by selectively ejecting ink drops onto an image substrate from a plurality of drop generators or inkjets arranged in a printhead or a printhead assembly. The ink may be directly ejected onto an image receiving media and then fixed to the media or the ink may be ejected onto an intermediate imaging member. The ink is subsequently transferred to image receiving media and then fixed to the media. A printhead controller generates firing signals that are delivered to the inkjet ejectors in a printhead to activate the inkjet ejectors selectively. The inkjets eject ink in response to the firing signals. The inkjets may eject liquid inks including, but not limited to, aqueous, solvent, oil based, liquefied solid ink, and curable ink.
A solid ink imaging device having an intermediate imaging member typically includes a drum maintenance unit (“DMU”). Previously known DMUs include an applicator, a wiper, and a reservoir for holding a release agent. Capillary forces deliver the release agent to the applicator, which applies the release agent to the surface of the intermediate imaging member. The wiper meters and smoothes the release agent on the surface of the intermediate imaging member. Once ejected, the ink coalesces on the layer of release agent on the intermediate imaging member. When the ink image and media pass through a nip formed between the intermediate imaging member and a transfer member, the ink image transfers from the intermediate imaging member to the media. In particular, the layer of release agent on the intermediate transfer member facilitates this transfer. After the image is transferred, the intermediate imaging member rotates to the DMU where more release agent is applied to the member and metered. The reapplication of release agent and the metering action of the wiper help lubricate the image receiving area of the intermediate imaging member as well as remove most excess oil, ink, and other debris that may have rested on the surface of the intermediate imaging member. In some cases, however, the tackiness of the coalesced ink may cause a portion of the ink, referred to herein as residual ink, to remain on the intermediate imaging member. During the next print job, some or all of the residual ink may transfer to a subsequent print medium and generate a latent version of the inkjet image. Also, a “ghosted” image may be present in the release agent remaining on the intermediate imaging member. The ghosted image may form a gloss defect in subsequent prints.
Generally, the typical DMU cycle sufficiently prepares the image receiving area of the intermediate imaging member for most print jobs. Some users are concerned about residual ink and/or ghosted images being transferred to subsequent media, especially when the content of an ink image is confidential or the like. Consequently, a continuing need remains in the art to develop methods and imaging devices configured to remove residual ink from the image receiving area of an intermediate imaging member more thoroughly, and also to disrupt any ghosted images in the release agent remaining on the intermediate imaging member subsequent to ink transfer.